Abstract
Nuclear bomb debris particles appearing in world-wide fallout act as excellent condensation nuclei, and this effect has been utilized for tracer studies of extensive precipitation systems. Synoptic type and climatological type samples have been examined, and the results strongly indicate that raindrop scavenging of low-level clouds, which have undergone little lifting, is an important mechanism in precipitation formation. For sea-level rain in western Norway a mean cloud rise after saturation of the order of 300 metres is indicated. DOI: 10.1111/j.2153-3490.1968.tb00366.x